1. Field of the Invention
The present invention relates to a tubeless lighting device, and in particular to a light-emitting diode (LED) based lighting device that has a tubeless structure for indoor and outdoor applications for lighting and features environmental conservation, power saving, and volume reduction.
2. The Related Arts
Fluorescent lamps are well known for indoor and outdoor applications for lighting. A conventional fluorescent tube gives off light by applying electrical discharging and requires various components, including a tube mount, tube connectors, and a ballast (transformer) and a starter. This leads to the disadvantages of being heavy and bulky and requiring a large amount of ferrous material. Further, the fluorescent tube contains therein mercury, which is considered a server environmental pollutant. Thus, the fluorescent tube, once disposed of, often leads to pollution to the environment. Further, a number of contacts must be formed among the tube, the tube connectors, the ballast, and the starter and such contacts present an increase of impedance that leads to unnecessary and additional consumption of power. This is the reason that the fluorescent tube gets high power consumption and a low power factor and this is also a cause for reducing the lifespan of the tube and the ballast.
Further, the conventional fluorescent tube uses tube connectors made of plastics, which are susceptible to deterioration due to high temperature, leading to structural instability, so that when the fluorescent is subjected to external vibration or earthquakes, the tube may unexpectedly fall and hurt people standing around. Thus, the total weight of lighting devices is often subjected to a limitation in applications where vibration/quake must be constrained. This leads to a constraint for the applications of the fluorescent tubes.
Solutions for such a problem are available in the market, such as Taiwan Utility Model Nos. M368749 and M365434, US Patent Publication No. 2007/0228999, which discloses a “retrofit LED lamp for fluorescent fixtures without ballast”, US Patent Publication No. 2007/0223225, which discloses a “LED lighting unit applied to a fluorescent lighting fixture” and U.S. Pat. No. 7,114,830, which discloses an “LED replacement for fluorescent lighting”. All these prior art references provide an LED based lighting module that is constructed in the form of a florescent tube for replacing the fluorescent tube. Such LED based solutions, although effectively eliminating the mercury based pollutant contained in the fluorescent tubes, require components, such as LED circuit boards, heat dissipaters, wires, and shades, that are not naturally decomposable and may thus cause an increase of the garbage in replacing lighting tubes and eventually lead to secondary pollution to the environments.
Those prior art references provide LED lighting tubes that still need the components used in the fluorescent lamps, such as tube mounts, tube connectors, ballasts, and starters, as well as wiring arrangements, so that the known LED lighting tubes are still of the disadvantages of being heavy and bulky, large consumption of ferrous material, having a large number of contacts, and short lifespan. Further, the LED based lighting tubes require LED circuit boards, heat dissipaters, wiring, and shades, all such components adding an undesired increase of overall weight, making it difficult to apply to environments where vibrations/quakes must be constrained. Further, the problem associated with structural instability between the tube and the tube connectors still exists that may cause underside hurting to a user. Thus, the known LED based lighting tube still suffers a number of drawbacks that must be overcome for a more prevailing trend of LED based lighting tubes.